Early on in the Syrian civil war, rebels wrested control of much of Northern Syria from the government of President Bashar al-Assad. This gave hope to a lot of people who desperately wanted a freer, brighter future, which is why the next phase of the war was so crushing. Islamic extremists with ties to al-Qaida came in and conquered many of the areas taken from the regime. The extremists targeted people affiliated with the regime and also activists who had helped start the uprising.

NPR's Alice Fordham went to Southern Turkey to meet some of the activists who say al-Qaida stole their revolution.

ALICE FORDHAM, BYLINE: You run into disenchanted revolutionaries all over Southern Turkey. I found some just across the Syrian border.

(SOUNDBITE OF PEOPLE TALKING)

FORDHAM: I'm sitting in a smoky living room in a house in Urfa. I'm surrounded by a group of about a dozen young guys, activists who've recently fled Syria. But they're not running away from Bashar al-Assad's forces, they're fleeing the group they know as Da'ash. And when they're together, they like to sing songs that remind them of the first demonstrations that they held years ago now. They've added a new one to their repertoire - about Da'ash.

(SOUNDBITE OF MUSIC)

UNIDENTIFIED MEN: (Singing in foreign language)

FORDHAM: The leader of Da'ash is a big thief, they sing. He arrests all the media activists.

This Da'ash is a pejorative nickname for an extremist super group that's hard-line even by al-Qaida standards. Officially, it's the Islamic State of Iraq and Syria. Last year, it took territory like these boys' hometown of Raqqah.

ABDULLAH FAT: They are threaten us, we will kill you. So we are run away.

FORDHAM: That's Abdullah Fat, a civil society activist. He imagined democracy in Raqqah, the only provincial capital controlled by rebels. But their hold was always shaky. And last year, this Da'ash - known by the English acronym ISIS - took control.

UNIDENTIFIED MAN #1: (Through Translator) When they took the city, a lot of our friends, activists, a lot of them were kidnapped and suddenly disappeared. We didn't know where they were. After that they started to kidnap a lot of lawyers, media activists. So we had to go.

FORDHAM: They say they were targeted because they were too Western. They documented alleged abuses by the extremists. The activists left after the mysterious death of one campaigner, Mohanned, whose work had inspired them all.

BASSIL: (Through Translator) It was like a message from ISIS because Mohanned was so active. And it was a message for all the activists. Eighty percent of the activists in Raqqah left after Mohanned got killed.

FORDHAM: That's Bassil. He wrote a song to remember Mohanned.

BASSIL: (Singing in foreign language)

FORDHAM: Mohanned is now a martyr, in a new robe. Please send some kisses to my brother and sister, the lyrics go, and we had enough of killing and arresting.

BASSIL: (Singing in foreign language)

FORDHAM: A couple hours away, in Gaziantep, another group of Raqqahans is wondering what to do next. When ISIS came to their town, it reminded them of Assad's forces.

UNIDENTIFIED MAN #2: (Through Translator) For example, in the regime days, we used to see the police cars. And not just police, the secret agency, the shabiha's cars. We were so afraid. In the time of Da'ash, we used to see those extremist cars with the big beards and they used to cover their faces in black and put heavy weapons on the cars. And we used to be very afraid.

FORDHAM: That middle-aged Raqqahan man says that ISIS took over the city hall. They dressed in an un-Syrian way, with long tunics and short pants. They encouraged more moderate Islamists to defect to them. Some had accents from Iraq, Yemen, Tunisia.

A younger guy, Khaldoun, says that ISIS started patrolling the university.

KHALDOUN: (Through Translator) They started by putting the girls on one side and the boys on the other side. And then they forced the girls to wear the niqab. And then they have these rules that if you say anything wrong against them, you should be punished.

FORDHAM: Raqqah was transformed. Posters appeared. One showed a woman entirely veiled in black, captioned: My Modesty, the Secret of My Beauty. Other posters praised Islamic law. Residents say the jihadis break fingers if they catch you smoking. About once a month, there's a public execution.

At first, Khaldoun and his friends had a few demonstrations against ISIS, but they say stopped after the extremists began firing grenades into the crowds.

KHALDOUN: (Through Translator) We were so confused because you know in the regime days, OK, that was so familiar, that is a criminal regime. But those men are from the revolution. We were always asking ourselves, how they can do this in the name of Islam. Why is this happening to our revolution?

FORDHAM: It isn't true that everyone hates ISIS. In the areas they control, they try to win hearts and minds. At a fun day in Aleppo last summer, there was an ice-cream eating contest. They deliver water, fuel and food to the needy. And some of the rebels just didn't want to fight such a strong adversary.

(SOUNDBITE OF PEOPLE TALKING)

FORDHAM: I meet Abu Khaled in the tiny flat he now shares with five other adults and 12 refugee kids. Before, he distributed food aid in Raqqah for a rival Islamist group. When ISIS came along, they were stronger.

ABU KHALED: (Through Translator) Yes, unfortunately. And they are organized like an army, like an official army. Their commands are not coming from people. It's strategy. They are so organized and they are so strong.

FORDHAM: Plus, a lot of the rebel fighters are devout Muslims. They saw no reason to fight these austere Islamists.

KHALED: (Through Translator) A lot of people in Raqqah believe they should not fight their brother in Islam. Some people said those people are not our enemy, the regime is our enemy. We should not fight Muslims.

FORDHAM: But eventually, the fight-back came. At the end of last year, Syrian militia groups coalesced into new alliances. They issued a challenge, and fighting began. Through January, there were skirmishes.

Journalist Ahmed Primo was in an ISIS jail in a commandeered children's hospital in Aleppo.

AHMED PRIMO: (Through Translator) On November 16th, in the middle of the night, some masked people attacked my home. When I asked, who are you, they said we are from the judicial courts. Then they took me to the children's hospital and I knew I was kidnapped by ISIS.

FORDHAM: Ahmed was held for two months and savagely beaten, he says, showing deep scars on his legs. When the militias began to fight ISIS, Ahmed could hear the battles getting closer. His jailers hauled people out of the cells in groups. Ahmed's name was called, but as the fighting intensified, the ISIS jailers fled. The rebel coalition overran the prison and Ahmed escaped. He later discovered that the other prisoners, about 50 of them, had been shot.

PRIMO: (Through Translator) I can't describe my feeling, because it's hard to describe, but what I'm thinking and believe, it's like a new baby that's come to life.

FORDHAM: Today, the fighting rages on, and ISIS is still strong in some places. In others, like Idlib in the west, they've taken a real hit. Here in the Turkish borderlands, revolutionary refugees like Ahmed have no idea what will come next.